Physics of the second day of junior high school is about air and medium

Your ideas and questions are very good. 、

Actually, there doesn't have to be air.

You can think of it this way. The reason why people think this way is that most of the sounds that people hear are eventually introduced into people's ears through the air, which causes the vibration of people's eardrums and makes people hear the sound.

Therefore, it seems that there must be air as a medium to spread sound.

First of all, you have to distinguish between the vibration of the medium and the vibration of the air in the sound. The reason why sound can spread is because the object vibrates and makes sound, which then causes the surrounding media (solid, gas, liquid, etc.). ) to vibrate, and then gradually spread out. This is a kind of vibration propagation.

And air is just a medium for spreading sound.

In fact, when people speak, the sound will reach people's ears through the bones.